1. Field of the Invention
This invention relates to a hard disk drive provided with a lock mechanism capable of locking a carriage at a prescribed position.
2. Description of the Prior Art
Hard disk drives are generally provided with a lock mechanism capable of locking a carriage at a prescribed position, for a magnetic head mounted on the carriage is required to be prevented from reaching a data zone of a magnetic disk while the power source of the hard disk drive is kept off service.
FIG. 4 and FIG. 5 show schematically conventional hard disk drive each provided with a lock mechanism capable of locking a carriage at a prescribed position. FIG. 4 shows the device as held in a state having the carriage locked in place and FIG. 5 shows the device as held in a state having the carriage left unlocked.
In these diagrams, 10 stands for a lock mechanism, 30 for a carriage, and 50 for a magnetic disk.
In the lock mechanism 10, a lock member 12 is rotatably supported in place by a shaft 14. The lock member 12 is provided at one end thereof with a claw 16 adapted for engagement with a projecting part 32 formed on a projecting member 40. A projecting member 40 is formed at the side of the carriage 30. Approximately to the middle of the lock member 12, a plunger 18 driven by a DC solenoid 16 is connected. A spring 20 adapted to urge the lock member 12 counterclockwise in the bearing illustrated is laid taut across the space intervening between the other end of the lock member 12 and the exterior of the DC solenoid 16.
The carriage 30 is rotated about a pivot 38 as the center by a drive mechanism comprising a magnet 34 and a VCM coil 36. This carriage 30 is provided on the lateral part thereof with the projecting member 40. The projecting member 40 is provided at the leading end thereof with the projecting part 32 which is adapted to be engaged with the claw 16 of the lock member 12 as described above. A magnetic head 42 is mounted on the leading end of the carriage 30.
The magnetic disk 50 is fixed on a spindle motor 54 by a disk retainer 52 and is rotated by the spindle motor 54. The surface of the magnetic disk 50 is divided into a data zone 56 and a contact start stop (CSS) zone 58. In the data zone 56, data are recorded and reproduced. While the power source for the hard disk drive is kept off service, the magnetic head 42 is positioned on the contact start stop (CCS) zone 58 and in the CCS zone 58 the magnetic head 42 is contacted with the surface of the magnetic disk 50.
The locking of the carriage 30 is started by rotating the carriage 30 thereby effecting retraction of the magnetic head 42 in the CSS zone 58. Consequently, the lock member 12 is rotated by the spring 20 counterclockwise in the bearing illustrated in the diagram. As the result, the carriage 30 is locked by the claw 16 of the lock member 12 being brought into engagement with the projecting part 32 formed on the carriage 30 (FIG. 4).
For release of this lock, the supply of electric current to the DC solenoid 16 is started again. Consequently, the lock member 12 is rotated clockwise in the bearing illustrated by the plunger 18 being drawn in the direction of A in the bearing shown in the diagram. As the result, the claw 16 falls away the projecting part 32 and the carriage 30 is unlocked (FIG. 5). Thereafter, the carriage 30 is rotated in such a manner as to move the magnetic head 42 to the data zone 56 and prepare the magnetic head 42 for recording and reproducing data.
Incidentally, since the lock mechanism in the hard disk drive constructed as described above has the DC solenoid, the plunger, etc. as its component elements, this hard disk drive suffers from undue numerousness of parts and entails difficulties such as high cost of production and complicate maintenance and inspection.
Further, the DC solenoid consumes electric power heavily and adversely affects the power consumption of the hard disk drive.